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FAQ

⇐ 123456 ⇒



:

int remove(const char *filename);

, filename. , .

:

int rename(const char *oldfilename, const char *newfilename);

; , . 0 (NULL) .

 

feof(), <stdio.h>. (1), ( EOF), (0), .

int feof(FILE * filename);

: Neg.dat

#include <stdio.h>

#include <stdlib.h>

void main(){

FILE *f_n;

int kol_vo = 0; // -

int value;

randomize();

f_n = fopen(Neg.dat, rb) //

if(!f_n) // 0 ( )

{puts( !\n);

exit(1);

}

while (!foef(f_n)); //

{fread(&value, sizeof(int), 1, f_n);

if(value < 0) kol_vo++;

}

printf( - = %d\n, kol_vo);

fclose(f_n);

}

-

/ <stdio.h> <cstdio>, /. / .2. / . : stdin, stdout, stderr.

 

2. , .

stdaux /
stderr
stdin
stdout
stdprn

stdin , stdout stderr .

/ :

- ;

- ;

- .

.

/ , . ( ) /. ftell() fgetpos() fseek() fsetpos(). . / (. .3).

3. / .

fread
fwrite
getc, fgetc
getchar stdin
putc, fputc
putchar stdout
fgets
gets stdin
fputs
puts stdout
fscanf
scanf stdin
sscanf
fprintf
printf stdout
sprintf

1) -

- :

int fgetc(FILE *fp);

fp , .

int fp. , EOF.

int fputc(int c, FILE*fp);

fp , ;

c int, .

fp int. , EOF.

 

.

#include "stdafx.h"#include <iostream>using namespace std;int _tmain(int argc, _TCHAR* argv[]){ FILE *f; int c; char *filename="t.txt"; if ((f=fopen(filename,"r"))==0) perror(filename); else while((c = fgetc(f))!= EOF) putchar(c); // fclose(f); system("pause"); return 0;}

 

2) -

- :

char *fgets(char *s, int n, FILE *f);

char *s , ;

int n ;

FILE *f , .

(n-1) '\n'. . '\0'. , 0.

int fputs(char *s, FILE *f);

char *s , ;

FILE *f , .

('\0') . EOF, , .

 

. f1.txt f2.txt.

#include "stdafx.h"#include <iostream>using namespace std;#define MAXLINE 255 // int _tmain(int argc, _TCHAR* argv[]){// in out FILE *in, // *out; // char buf[MAXLINE]; //, in=fopen("f1.txt","r"); // out=fopen("f2.txt","w"); // while(fgets(buf, MAXLINE, in)!=0) // in buf fputs(buf, out); // buf out fclose(in); // fclose(out);// system("pause"); return 0;}

3) -

- :

int fread(void *ptr, int size, int n, FILE *f);

void *ptr , ;

int size ;

int n ;

FILE *f , .

, EOF.

int fwrite(void *ptr,int size, int n, FILE *f);

void *ptr , ;

int size ;

int n ;

FILE *f , .

, EOF.

 

.

#include "stdafx.h"#include <iostream>using namespace std;struct Employee {char name[30]; char title[30]; float rate; };int _tmain(int argc, _TCHAR* argv[]){ Employee e; FILE *f; if((f=fopen("text.dat","w"))==NULL) { printf("\n "); } int n; // printf("\n N="); scanf("%d",&n); for(int i=0;i<n;i++) { // printf(":");scanf("%s",&e.name); printf(":");scanf("%s",&e.title); printf(":");scanf("%f",&e.rate); // fwrite(&e,sizeof(Employee),1,f); } fclose(f); // if((f=fopen("text.dat","rb"))==NULL) printf("\n "); while(fread(&e,sizeof(Employee),1,f)) printf("%s, %s, %f;\n", e.name, e.title, e.rate); fclose(f); system("pause"); return 0;}

4) -

, .. , . -:

int fprintf(FILE *f, const char *fmt, par1, par2,...);

FILE*f , ;

const char *fmt ;

par1, par2,... , .

 

int fscanf(FILE *f, const char *fmt, &par1, &par2,...);

FILE*f , ;

const char *fmt ;

par1, par2,... , .

 

.

#include "stdafx.h"#include <iostream>using namespace std;int _tmain(int argc, _TCHAR* argv[]){ FILE *f; int n, nn,m; if((f=fopen("int.dat","w"))==0) perror("int.dat"); for(n=1;n<11;n++) fprintf(f, "\n%d %d", n, n*n); fclose(f); if ((f=fopen("int.dat","r"))==0) perror("int.dat"); m=1; while(fscanf(f, "%d %d",&n, &nn)&& m++<11) printf("\n%d %d",n,nn); fclose(f); system("pause"); return 0;

3.2.2 :

, \n.

:

-

- .

, (FAT).

 

.

, fprintf() fscanf()

/ fprintf() fscanf() printf() scanf(), , .

, .

#include <stdio.h>

#include <conio.h>

#include <stdlib.h>

void main(){

FILE *f;

int dig;

if (f = fopen(inp_f, r) == NULL) //

{ printf( !\n);

exit(0);

}

fscanf(f, %d, &dig); // dig

fclose(f); //

f = fopen(out_f, w);// .

fprintf(f, %d, dig);

fclose(f); //

}

 

, . . .

: , , .

#include <stdio.h>

#include <conio.h>

#include <stdlib.h>

#include <string.h>

 

void main(int argc, char *argv[]){

FILE *f_in, *f_out;

int ch;

char *name; //

int count = 0; //

if (argc<2) //

{ printf( );

gets(name);

}

else name = argv[1]; //

if ((f_in = fopen(name, r))!= NULL) //

{ strcat(name, .out); // .out

//

f_out = fopen(name, w); //

while((ch = fgetc(f_in)!=EOF)

if(count++%3 == 0)

fputc(ch, f_out); // 3-

fclose(f_in);

fclose(f_out);

}

else printf( !\n);

}

 

, .

.

#include <stdio.h>

#include <conio.h>

#include <stdlib.h>

#include <string.h>

void main(int argc, char *argv[]){

FILE *f_in;

char buffer[256]; // - 255

char *name; //

if (argc<2) //

{ printf( );

gets(name);

}

else name = argv[1]; //

if ((f_in = fopen(name, r))!= NULL) //

{ while(fgets(buffer, 255, f_in))!= NULL)

{fputs(buffer, stdout);

fputs(\n, stdout);

}

fclose(f_in);

else printf( !\n);

}

 

while : fgets() fputs()

, . , , , , , . . fflush(f_out). flushall().

fclose(f_out) , .. .

 

. , . , . ( ): 20 , 5 , , 40 .

s, mon () . .

#include <iostream.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

int main()

FILE *fi, *fo;

if ((fi = fopen(d:\\c\\file.txt, r)) == 0){

cout << ; return 1;}

if ((fo = fopen(d:\\c\\binfile.out, w+b)) == 0){

cout << ; return 1;}

const int dl = 80;

char s [dl];

struct{

char type [20];

int opt, rozn;

char comm[40];} mon;

int kol = 0; //

while (fgets (s, dl, fi)){

//

strcnpy(mon.type, s, 19);

mon.type[19]=\0;

mon.opt = atoi(&s[20]);

mon.rozn = atoi(&s[25]);

strcnpy(mon.comm, &s[30], 40);

fwrite(&mon, sizeof mon, 1, fo);

kol++;

}

fclose(fi);

int i; cin >>i; //

if (i >= kol){ cout << ; return 1;}

// i:

fseek (fo, (sizeof mon)*i, SEEK_SET);

fread (&mon, sizeof mon,1, fo);

cout << type << mon.type <<opt << mon.opt

<< rozn << mon.rozn << endl;

flose (fo);

return 0;

}

⇐ 123456 ⇒


:

: 2016-11-18; !; : 880 |

:

:

- , 20 40 . - .
==> ...

1621 - | 1580 -


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